Electrical traffic analysers



Dec. 10, 1968 L. J. ROBSON 3,416,137

ELECTRICAL TRAFFIC ANALYSERS Filed Nov. 27. 1964 VBI 7-5K r VCl 7. K

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United States Patent 3,416,137 ELECTRICAL TRAFFIC ANALYSERS Leslie John Robson, Sutton, Surrey, England, assignor to Automatic Switching Limited, London, England, a British company Filed Nov. 27, 1964, Ser. No. 414,349 Claims priority, application Great Britain, Nov. 29, 1963, 47,281/ 63 3 Claims. (Cl. 340-172) ABSTRACT OF THE DISCLOSURE An electrical traffic analyser circuit comprising a pair of polarized relays each having a pair of ditferentially connected coils and contacts connected to act consecutively to energize separate pulse counters under predeter- {mined load conditions. The load conditions to which the This invention relates to traffic analysers for recording the utilization, e.g., of radio, telephone and telegraph circuits including public exchange lines and rented private wires terminated in private branch exchanges.

The present invention consists in an electrical trafiic analyser comprising means for indicating the length of time for which a group of circuits is engaged to a particular extent.

Thus, there could be the time the group is fully engaged or the time any particular number of lines is free and available or two or more such indications could be given.

By this means the grade of service can be assessed and frequent analysis will establish the trend of the service enabling advance adjustments of the system to, be made according to operational or economic requirements.

The invention will be further described with reference to the accompanying drawing which is a circuit diagram of an embodiment of the invention.

It is assumed that sensing relays VA, VB, VC and so on (not shown) are associated with the respective circuits of a group of circuits, and operate whenever the circuits with which each is associated become engaged. Likewise they restore to their normal positions when their associated circuits revert to the free line condition. Contacts VAl, VBl, VC1 and so on of these sensing relays are each connected to earth over its 7,500 ohm resistance and the contacts are commoned and connected to the tag b of a coil a-b of one or more polarised relays (here two are shown PA/l and PB/ 1). Tag a of the coil is connected to battery.

The polarised relays have two coils a-b and c-d each having an equal number of turns and ohmic resistance.

The polarised relays PA, PB have, conveniently, single changeover contacts respectively PA1 and FBI and are ,of the one side stable type such that with positive potential applied to, say, coil tag a or c its relay contact 2 makes contact with 3.

However, if equal and opposite potentials are applied to both coil tags such that negative is applied to tag a and positive to tag c the relay will remain in its normal 3,416,137 Patented Dec. 10, 1968 position and will maintain this position even it the current in coil a-b is increased to saturation point.

If, however, the current in winding c-d is increased by a certain critical amount over that of winding a-b the relay will operate. The relay can then be restored to normal by increasing the current in winding ab by a similar amount. A further critical current increase over its winding c-d causes it to operate once again and so on.

The tags a of the polarised relays are connected to battery and the tags 0 are connected to respective wipers a, b a two-pole four position switch SW1. The respective contacts 1, 2, 3 and 4 of wiper a are connected to earth via 15,000 ohms, 7,500 ohms, 5,000 ohms and 3,750 ohms and the respective contacts 1, 2, 3 and 4 of wiper b are connected to 7,500 ohms, 5,000 ohms, 3,750 ohms and 3,000 ohms.

Pulsing contacts PC are arranged to connect earth at the rate of one impulse per second to the moving contact PA1. The normally open fixed contact of PA1 is connected over :a counter CA to battery.

The normally closed fixed contact is connected to the moving contact of PB1. The normally open fixed contact of FBI is connected over a counter CB to battery.

Preset switch SW1 is shown in position 1. In this position operation of the polarised relay PA and the asvsociated electro-mechanical counter CA will occur only vwhen the current in coil c-d exceeds that in coil a-b. This will occur only when all channel sensing relays are in the operated position and coil a-b is thereby open circuit.

Polarised relay PB on the other hand will operate ,when one line only is free, i.e., when one channel sens- ,ing relay only is in its normal position since under this condition the current in relay PB coil c-d will exceed that in coil a-b and thus cause it to operate and thereby pulse-operate counter CB. The relay will operate also on the no lines free condition but the simultaneous operation of PA1 prevents recording on counter CB.

To take a further example of the circuits mode of operation, switch SW1 is preset to position 4. As previously described polarised relay PA will operate only when the current in coil c-d exceeds that of coil a-b. In this case the resistance connected in series with coil c-d is comparatively low of 3,750 ohms and hence a proportionately greater number of sensing relays will require to be in their normal position before the current in coil a b exceeds that in coil c-d to release relay PA to the normal position. This will not occur until four or more lines are free.

Relay PA will remain operated therefore whilst three or less lines are free. Relay PB, on the other hand, will still remain operated at four lines free since the series resistance connected to its c-d coil is 3,000 ohms.

When five or more lines become free, however, relay PB will also release as the current in its coil a-b will exceed that of coil c-d and registration will not occur on either counter until the condition of four or less lines .free again occurs.

Thus the circuit conditions controlling the operation of the polarised relays are determined by the setting of switch SW1 (positions 1, 2, 3 and 4 only are shown but this number can be extended as desired) and this will cause a response to whatever number of free lines occurthe group the condition will exist to operate counter CB and that the position in the group of the free line has no effect on the condition. Similarly it will be seen that if two or more lines are free neither counter will operate.

Similarly in position 2 of the switch SW1 counter CA will record whenever the group is fully engaged or has only one line free whilst counter CB will record when only two lines :are free. Any additional number of lines free will not cause the operation of either counter.

Position 3 will record on CA two lines or less free and on CB three lines only free.

Position 4 will record on CA three lines or less free and on CB four lines only free.

And so on depending on the number of conditions required to be sensed by provision of additional switch positions. It will be seen that variations of resistance values can be made to extend the number of free circuits at which the sensing relays operate through its system of detection of small controlled incremental voltages.

Various modifications may be made within the scope of the invention.

I claim:

1. An electrical trafiic analyser circuit comprising means for attaching parallel connected and identically resistive load lines to the circuit; means providing an output record indicating the length of time for which a group of said load lines is engaged to a particular extent; an energization circuit connected to each output record means; two polarised relays of the one-side stable type each having a pair of coils; energization circuits for each of said coils; means connecting said relays for consecutive operation; one of said relay coils being serially connected with a group of said resistive load lines; a multi-position switch including banks of electrical wiper contacts and wipers associated with respective banks and ganged together; a difiercnt value of electrical resistance connected to each of said wiper contacts; leads connecting said ganged wipers one to each of the other of said pair of relay coils to introduce into the energization circuits of such latter coils different resistances for different positions of said multi-position switch; and said polarized relays having contacts connected in series in the energization circuit of said output record means and operated by said relays to complete said record means energization circuit during predetermined load conditions.

2. A circuit as set forth in claim 1, in which said output record means comprises two recorders; and one of said relay contacts is a change-over contact and operates to make and break the energization circuit of one of said recorders of said output record means and to close the energization circuit of the contacts of the other of said relays when breaking the energization circuit of said one recorder; said consecutive operation of said other relay closing contacts thereof connected to energize the other of recorders of said output record means to signify commencement of a period which is terminated by opening .of the contacts of said other relay at the end of said period.

3. An electrical circuit providing an output signal in response to the occurrence of a particular load condition in a range of load conditions each denoted by a different electrical resistance applied to the circuit which comprises: two polarised relays of the one-side stable type; means connecting said relays for consecutive operation; a pair of coils on each of said relays; means connecting one of said coils of each relay to said load; energization circuits for each of said coils; a multi-position switch; banks of electrical wiper contacts associated with said switch; different values of electrical resistance connected to the contacts of each of said banks; ganged wipers associated with respective banks and electrically connected one to each of the other coils of each pair of relay coils to introduce into said energization circuits of the other of each pair of relay coils different resistances for dilferent switch positions; and serially-connected relay contacts operated by said polarized relays and arranged to complete an electrical output circuit only during the period between consecutive operation of the relays.

References Cited UNITED STATES PATENTS 1,900,095 3/1933 Brownstein 340l72 2,490,048 12/1949 Gohorel 340172 2,556,697 6/1951 Oberman et a1. 340172 2,923,919 2/1960 Langdon 340-172 OTHER REFERENCES German printed patent application 1,142,914, Jan. 31, 1963.

JOHN W. CALDWELL, Primary Examiner.

D. I. YUSKO, Assistant Examiner.

US. Cl. X.R. l798 

